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Autonomous driving is no longer simply a concept. Self-driving vehicles are already hitting the road in some countries. The connected car is already here in many ways: advanced telematics and advanced driver-assistance systems (ADAS) are becoming increasingly available on a wide range of vehicles, and vehicle-to-everything (V2X) is almost a reality. This article focuses on enabling technologies which are paving the way towards vehicles of the future.

Sensor fusion

The adoption of sensors, a fundamental component of ADAS systems, is pushing up the overall electronic content of newer vehicles. This is made possible by advances in electronics, which enable lighter, smaller and more affordable sensor solutions. Sensors in ADAS play a vital role in enhancing situational awareness, thereby improving safety of both drivers and other road users.

Increased use of sensors will drive cost further down, leading to more vehicles having them fitted. In automotive, ultrasound sensor technology is highly mature. Ultrasound sensors are widely used, given their affordability and simple implementation. Due to the propagation characteristics of sound, ultrasonic sensors are only used in short range and low speed applications (for instance, self-parking and blind spot detection).

Since the introduction of radar for automotive, radar sensors have become an integral part of ADAS. They are used in the short, mid and long-range detection of stationary and moving objects, providing important information, including distance, angle and velocity.

Unlike technologies such as LiDAR and other vision systems, they are less affected by weather and lighting conditions. Due to its robust sensing capabilities, radar is used in numerous safety applications – including adaptive cruise control, collision avoidance and autonomous emergency braking.

Automotive short-range radar systems are currently permitted to operate in two frequency bands, namely K band (24 GHz) and W band (79 GHz). The use of the lower frequency K band will, in 2022, be phased out of new vehicles in Europe, to protect other users in the 24 GHz band. The move towards higher frequencies not only alleviates spectrum crowding and interference in the lower frequencies, it also provides benefits such as smaller sensors and the allowance for higher spatial resolution with wider operating bandwidths.

LiDAR and infrared are emerging technologies for automotive applications. Neither is yet extensively used, due to high cost.

LiDAR sensors provide high-resolution 3D imaging, which will be critical for autonomous driving. However, like camera sensors, they are sensitive to weather conditions.

Infrared sensors, on the other hand, provide night vision capabilities. These sensor technologies will need to become more affordable to be attractive for widespread use in automotive.

Since different sensors have their own specific advantages and limitations, the industry is adopting the use of multiple types of sensors: these complement each other’s unique strengths, ultimately reducing the effects of any limitations. This trend has been termed ‘sensor fusion’ (see Figure 1 – links to online magazine version). The diversity and redundancy in sensor fusion is considered necessary to enable more accurate and reliable perception of the vehicle’s surroundings.

V2X communications

Autonomous vehicles require increased connectivity beyond ADAS’s network of sensors. V2X is a key technology enabler to enhance the vehicle’s perception of its surroundings, enabling it to communicate with other vehicles and its environment.

The concept involves vehicles exchanging messages and data – not only to and from other vehicles (V2V) – but with the network (V2N), pedestrians (V2P) and infrastructure (V2I). There are potential lifesaving benefits as V2X communication brings new levels of situational awareness, leading to increased road safety, as well as traffic efficiency.

Wi-Fi radio access technology was initially selected as a candidate for V2X for its direct communication among nodes and low latency. The new derivative standard, IEEE 802.11p (also termed as ITS-G5 in Europe or DSRC in North America), was specified and designed to meet stringent performance specifications required for Intelligent Transport Systems (ITS) applications. Many field trials have been carried out in the recent years, making the Wi-Fi-based V2X relatively mature – and almost ready for deployment.

Presently, cellular V2X (C-V2X) – based on R14 of 3GPP Long Term Evolution (LTE) cellular technology – is also making its case as a contender for V2X communication.

Proponents of C-V2X highlight some of the advantages of a cellular-based system over an ad-hoc Wi-Fi-based system (better security, congestion control, reliability, and so on), as well as the ability to leverage the existing cellular infrastructure (V2N).

In addition, 3GPP R14 enhances the ‘PC5 Sidelink’ interface for Direct Communications allowing V2V communications between vehicles. Finally, as part of the 3GPP standards family, C-V2X offers an evolution path to 5G.

There are, therefore, two distinct technologies to be considered for Cooperative ITS (C-ITS): 802.11p and C-V2X. While there is a debate on which technology is better suited for V2X, there is also interest in making both technologies co-exist – to leverage the best of both worlds.

V2X communication is considered necessary to attain higher levels of automation (SAE J3016), as this gives vehicles non-line-of-sight awareness – enhancing both the driver’s, and any autonomous system’s, situational awareness. It is predicted that 5G, which will be URLLC (ultra-reliable low latency communication) technology, will bring about even more enhanced safety performance from the network.

Secure in-vehicle communication networks

Modern vehicles are powered by continuous growth in electronics and embedded software. Automotive applications like surround view, on-board diagnostics, infotainment and telematics are all driving up bandwidth requirements. With increasing intelligence – enabled of course by sensor fusion and V2X communications – comes the need for a reliable high-speed communication network, to support real-time transfer and data processing within the vehicle.

The OPEN (One Pair EtherNet) Alliance was formed to establish automotive Ethernet as an open standard, and to encourage widescale adoption of Ethernet connectivity in automotive.

Ethernet is a relatively recent in-vehicle point-to-point communication technology. It was introduced to address increasing need for bandwidth, coupled with reduced cost, weight and complexity (as compared to existing in-vehicle wired communication technologies). The modular setup of Ethernet transceivers, switches and controllers also allows for scalability and flexibility.

The Ethernet communication network is seen as a key infrastructure component for future autonomous driving and the connected car. The trend for automotive wiring harnesses is moving from heterogeneous networks of proprietary protocols (such as CAN, MOST) to hierarchical homogeneous automotive Ethernet networks (as shown in Figure 3).

The IEEE standards association is currently working to add time sensitive networking (TSN) functionality to the existing standards for 802.1 and 802.3 Ethernet, which will provide deterministic performance: a vital component for real-time, mission critical applications. With the inclusion of TSN functionality, Ethernet is poised to become the core network backbone – fundamentally meeting the complex demands of future vehicles.

Keysight works with the world’s leading automotive electronics companies throughout the automotive ecosystem – helping them drive their innovations, from design, to test, to market – faster, and at a lower cost. Technologies include wireless, 5G, RF, millimetre wave, automotive Ethernet, high-speed digital, optic, power component, power conversion, battery, EV/HEV, functional test, and more – and many of these enabling technologies are helping facilitate the future of connected and autonomous vehicles.

V2X is a key technology enabler to enhance the vehicle’s perception of its surroundings, enabling it to communicate with other vehicles and its environment – offering potential lifesaving benefits and new levels of situational awareness.